Exemplary embodiments relate to distinguishing computers and humans, and more specifically, to tests for distinguishing computers and humans.
CAPTCHA stands for “Completely Automated Public Turing Test to Tell Computers and Humans Apart”, and CAPTCHAs are designed to tell the difference between humans and a computer program based on their respective abilities to solve a problem. CAPTCHAs are commonly used on Web pages where people register for an account, like email sites such as Yahoo®, Microsoft®, and Google®. Their purpose is to prevent (or slow) the use of programmed registrations which are then commonly used for spam and other uses depending on the Web site. The use of CAPTCHAs is expected to grow, and future use can be expected in various virtual environments such as, e.g. Second Life®. The most common type of CAPTCHA is implemented by asking the user to look at an image and type the alphabetic or numeric characters in it. Improved character recognition software can now circumvent this basic CAPTCHA, and there is now a need for a new generation of CAPTCHA tests.
There is now a movement from simple character recognition to image recognition CAPTCHAs. It is presumed that hackers will work to exploit this and improve their image recognition software (just like they improved character recognition). There is a race between CAPTCHA developers and spammers.